This invention relates to terminal retention in connectors and particularly primary terminal retention.
In connectors, it is common to have a primary terminal retention feature that retains the individual terminals in their respective terminal passageways. Connectors typically hold a plurality of terminals, this primary retention feature enables each terminal to be held in place once loaded into the connector while the other terminals are being loaded in their respective passageways. In high vibration environments or in applications where it is likely that there may be additional forces excerpted on the terminal that tend to dislodge the terminal from the terminal receiving passageway, it is also common to incorporate a secondary locking member as part of the connector assembly. A common form of a secondary locking member involves a structure having a shoulder that is moveable into the passageway in order to provide an obstruction therealong would interfere with a complementary shoulder on the contact and thereby prevent withdraw.
An example of an electrical connector of this type is illustrated in EP 0 510 583 where a generally rectangular terminal block has a number of electrical terminal receiving cavities with primary connection means disposed along the longer sides of the terminal block and corresponding to each of the respective cavities in order to retain the electrical terminals therein. The primary connecting means are integrally moulded resilient arms having a latching tab thereupon to engage the contact when it is inserted. Additionally, a secondary locking structure is provided by a flexible hinged flap having a plurality of comb-like teeth thereupon which extend through holes in the terminal block and into the passageway to obstruct the passageways, thereby preventing the terminal from being removed from the terminal block.
In general, there is trend toward reducing the size of connectors. For various reasons, it may not be possible to reduce the spacing between the terminals positioned within the connector. Therefore, it is desirable to minimise the outside profile of the terminal block. This presents a number of problems to connectors such as that disclosed in the aforementioned reference. First of all, as the outer profile becomes smaller, the wall in which the primary retention means is disposed becomes thinner. This makes it difficult to form the integrally moulded latch arm. Additionally, when a primary retention arm and an opening for secondary locking is provided the structural integrity of the terminal block is reduced.
Therefore, it is desirable to improve upon the existing connectors by providing effective primary terminal retention in terminal blocks having thin walls. It is a problem with connectors such as that disclosed above to provide primary terminal retention in generally rectangular connectors where the longitudinally extending walls are close to the terminal passageways so that it is not easily to form primary connecting means therein. It is a problem with connectors as disclosed in the aforementioned reference that as the wall becomes thinner, the amount of material available for the forming of the resilient arm with the latch thereupon is reduced, these primary retention members become susceptible to overstress damage and it s desirable to prevent such failure.
It is important to note however that while the aforementioned reference is directed to an electrical connector and that is the most common application of connectors, the problems set out above also apply to fibre optic connectors and the present invention is applicable to connectors in general. The terminals described herein are meant to be generic and could be either for the termination of optical or electrical cables.
At least the first problem set out above is solved by providing a connector for receiving terminals therein, the connector comprising a terminal block having outer walls and opposing ends walls, a terminal receiving passageway extending between the opposing end walls for receiving a terminal therein, and a primary retention member disposed along the passageway having a resilient retention arm extending into the passageway to retain their terminal therein, the connector being characterised in that the primary retention member is formed from a generally flat plate and includes a body set in the terminal block and the retention arm extends from the body into the passageway.
At least the second problem set out above is solved by providing a connector for receiving terminal therein, the connector comprising a terminal block having outer side walls that intersect to define corners and opposing end walls, a terminal receiving passageway extending between the opposing end walls for receding a terminal therein, and a primary retention member disposed along at least one of the terminal receiving passageways and having resilient retention arm extending into the passageway to retain the terminal therein, where the at least one passageway is located in the vicinity of one of the corners, the connector is characterised in that primary retention member is disposed between the one of the corners and the one passageway in the vicinity of the corner.
At least the third problem set out above is solved by providing a connector for receiving terminals therein, the connector comprising a terminal block having outer side walls and opposing end walls with terminal receiving passageways extending therethrough, primary retention members are disposed along respective passageways and include an moulded resilient latch arm formed integrally with terminal block that extends into the passageway to prevent withdraw of the inserted terminal, the connector characterised in that the terminal block includes a post located behind the resilient latch arm to prevent overstress.
It is an advantage of the present invention that an effective primary retention of terminals in a terminal block may be achieved even when the walls adjacent the terminal receiving passageways are relatively close thereto. It is yet another advantage of the invention that the primary retention member may be stamped and formed from a thin sheet of metal. It is another advantage of the invention that by providing a primary retention member in the vicinity of the corner, additional material of the terminal block is available in order to establish the primary retention. It is another advantage of the invention that by providing a post behind a resilient latch arm of the primary retention member to prevent overstress, smaller latch arms may be used.
It is still yet another advantage that secondary locking may be included in a connector of this type. In particular, it is possible to incorporate a secondary locking member upon a cover as set out in one of the alternative embodiments.